U.S. patent number 9,608,628 [Application Number 13/982,473] was granted by the patent office on 2017-03-28 for capacitive touch panel with improved visibility.
This patent grant is currently assigned to LG HAUSYS, LTD.. The grantee listed for this patent is Jung Cho, Yong-Bae Jung, In-Sook Kim, Min-Hee Lee, Seong-Hoon Yue. Invention is credited to Jung Cho, Yong-Bae Jung, In-Sook Kim, Min-Hee Lee, Seong-Hoon Yue.
United States Patent |
9,608,628 |
Yue , et al. |
March 28, 2017 |
Capacitive touch panel with improved visibility
Abstract
The present invention provides a capacitive touch panel and a
manufacturing method thereof, wherein the capacitive touch panel
includes a first transparent substrate in which an upper
transparent electrode and an upper metal interconnect electrode are
formed on the lower side thereof; a transparent adhesive portion;
and a second transparent substrate in which a lower transparent
electrode and a lower metal interconnect electrode are formed on
the upper side thereof. More specifically, the invention provides a
capacitive touch panel with excellent visibility since an expensive
ITO transparent electrode is replaced with conductive materials
such as CNT and graphene and the touch panel has an electrode
pattern of a specific structure.
Inventors: |
Yue; Seong-Hoon (Seongnam-si,
KR), Jung; Yong-Bae (Ulsan, KR), Kim;
In-Sook (Gyeonggi-do, KR), Lee; Min-Hee
(CheonGunpo-si, KR), Cho; Jung (Seoul,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Yue; Seong-Hoon
Jung; Yong-Bae
Kim; In-Sook
Lee; Min-Hee
Cho; Jung |
Seongnam-si
Ulsan
Gyeonggi-do
CheonGunpo-si
Seoul |
N/A
N/A
N/A
N/A
N/A |
KR
KR
KR
KR
KR |
|
|
Assignee: |
LG HAUSYS, LTD. (Seoul,
KR)
|
Family
ID: |
47437556 |
Appl.
No.: |
13/982,473 |
Filed: |
July 4, 2012 |
PCT
Filed: |
July 04, 2012 |
PCT No.: |
PCT/KR2012/005294 |
371(c)(1),(2),(4) Date: |
July 29, 2013 |
PCT
Pub. No.: |
WO2013/005979 |
PCT
Pub. Date: |
January 10, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130306461 A1 |
Nov 21, 2013 |
|
Foreign Application Priority Data
|
|
|
|
|
Jul 4, 2011 [KR] |
|
|
10-2011-0066139 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F
3/0446 (20190501); H03K 17/962 (20130101); G06F
3/0445 (20190501); G06F 2203/04103 (20130101); Y10T
156/10 (20150115) |
Current International
Class: |
G06F
3/045 (20060101); H03K 17/96 (20060101); G06F
3/044 (20060101) |
Field of
Search: |
;200/600 ;345/174 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2005070821 |
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Mar 2005 |
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JP |
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2008098169 |
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Apr 2008 |
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JP |
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2009271918 |
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Nov 2009 |
|
JP |
|
2010176571 |
|
Aug 2010 |
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JP |
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2010282729 |
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Dec 2010 |
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JP |
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10-2005-0084370 |
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Aug 2005 |
|
KR |
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10-2009-0115048 |
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Nov 2009 |
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KR |
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10-2010-0082514 |
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Jul 2010 |
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KR |
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20100082514 |
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Jul 2010 |
|
KR |
|
10-2010-0095988 |
|
Sep 2010 |
|
KR |
|
2011078170 |
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Jun 2011 |
|
WO |
|
Other References
KR101066111B1 translation--(original Sep. 2011). cited by examiner
.
Japanese Office Action dated Jul. 1, 2014. cited by applicant .
Japanese Notice of Allowance dated Jan. 20, 2015. cited by
applicant .
International Search Report mailed Dec. 21, 2012 for
PCT/KR2012/005294. cited by applicant.
|
Primary Examiner: Luebke; Renee
Assistant Examiner: Caroc; Lheiren Mae A
Attorney, Agent or Firm: Hauptman Ham, LLP
Claims
the invention claimed is:
1. A capacitive touch panel comprising: a first transparent
substrate having an upper transparent electrode and an upper
metal-interconnect electrode on a lower surface thereof; a
transparent adhesive portion; and a second transparent substrate
having a lower transparent electrode and a lower metal-interconnect
electrode on an upper surface thereof, wherein the lower
transparent electrode comprises a conductive composition, wherein
the upper transparent electrode consists of indium tin oxide (ITO),
and the lower transparent electrode consists of carbon nanotubes
(CNTs) or graphene, wherein the upper transparent electrode
comprises rhombic patterns and upper connectors disposed between
the rhombic patterns to connect the rhombic patterns, wherein the
lower transparent electrode comprises octagonal patterns and lower
connectors disposed between the octagonal patterns to connect the
octagonal patterns, and each octagonal pattern shares a common
sidewall with at least one adjacent octagonal pattern, wherein the
lower connectors are the common sidewalls between adjoining
octagonal patterns which are continuously arranged, wherein each
rhombic pattern of the upper transparent electrode has a smaller
area than each octagonal pattern of the lower transparent
electrode, and wherein the rhombic patterns of the upper
transparent electrode and the octagonal patterns of the lower
transparent electrode do not overlap each other.
2. The capacitive touch panel according to claim 1, wherein the
first or second transparent substrate comprises at least one of
glass, polyethylene terephthalate (PET), polyethylene naphthalate
(PEN), polyimide (PI), and acryl.
3. A method of manufacturing a capacitive touch panel, the method
comprising: forming an upper transparent electrode and an upper
metal-interconnect electrode on a lower surface of a first
transparent substrate; forming a lower transparent electrode and a
lower metal-interconnect electrode on an upper surface of a second
transparent substrate; and bonding the first transparent substrate
to the second transparent substrate, wherein the lower transparent
electrode comprises a conductive composition, the upper transparent
electrode comprises indium tin oxide (ITO), and the lower
transparent electrode comprises carbon nanotubes (CNTs) or
graphene, wherein the upper transparent electrode and the lower
transparent electrode are formed on the lower and upper surfaces of
the first and second transparent electrodes, respectively, by one
method selected from the group consisting of spraying coating,
air-jet coating, and rotary screen coating, wherein the upper
transparent electrode is formed comprising rhombic patterns and
upper connectors disposed between the rhombic patterns to connect
the rhombic patterns, the lower transparent electrode is formed
comprising octagonal patterns and lower connectors disposed between
the octagonal patterns to connect the octagonal patterns, and each
octagonal pattern shares a common sidewall with at least one
adjacent octagonal pattern, wherein the lower connectors are the
common sidewalls between adjoining octagonal patterns which are
continuously arranged, wherein each rhombic pattern of the upper
transparent electrode is formed having a smaller area than each
octagonal pattern of the lower transparent electrode, and wherein
the rhombic patterns of the upper transparent electrode and the
octagonal patterns of the lower transparent electrode do not
overlap each other.
4. The method according to claim 3, wherein the first or second
transparent substrate comprises at least one of glass, polyethylene
terephthalate (PET), polyethylene naphthalate (PEN), polyimide
(PI), and acryl.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application claims the priority of Korean Patent Application
No. 10-2011-0066139, filed on Jul. 4, 2011 in the KIPO (Korean
Intellectual Property Office). Further, this application is the
National Phase Application of International Application No.
PCT/KR2012/005294 filed Jul. 4, 2012, which designates the United
States and was published in Korean. Both of the priority documents
are hereby incorporated by reference in their entireties.
TECHNICAL FIELD
The present invention relates to a capacitive touch panel, and more
particularly, to a capacitive touch panel which employs a patterned
transparent electrode coated with a conductive composition to
improve visibility.
BACKGROUND ART
A conventional capacitive touch panel using an ITO transparent
electrode has problems of poor visibility due to overlap between a
sensing pattern on an upper side and an operation pattern on a
lower side. Further, although an upper metal-interconnect electrode
and a lower metal-interconnect electrode are arranged in a parallel
form to reduce resistance, excessive increase in fraction of a
parallel circuit reduces total resistance and thus can deteriorate
touch sensitivity. Moreover, if the ITO transparent electrode is
replaced with CNT or graphene, such problems become more serious
and visibility thereof may also be deteriorated due to inherent
properties of such materials.
Therefore, there is a need for an electrode pattern structure which
employs a conductive material such as CNT or graphene as a
replacement for an ITO transparent electrode while securing high
visibility.
DISCLOSURE
Technical Problem
It is an aspect of the present invention to provide a capacitive
touch panel which employs a conductive material such as CNT or
graphene as a replacement for an expensive ITO transparent
electrode and has an electrode pattern of a particular structure,
thereby providing high visibility.
Technical Solution
In accordance with one aspect of the present invention, a
capacitive touch panel includes: a first transparent substrate
having an upper transparent electrode and an upper
metal-interconnect electrode on a lower surface thereof; a
transparent adhesive portion; and a second transparent substrate
having a lower transparent electrode and a lower metal-interconnect
electrode on an upper surface thereof, wherein the lower
transparent electrode includes a conductive composition.
In accordance with another aspect of the present invention, a
method of manufacturing a capacitive touch panel includes: forming
an upper transparent electrode and an upper metal-interconnect
electrode on a lower surface of a first transparent substrate;
forming a lower transparent electrode and a lower
metal-interconnect electrode on an upper surface of a second
transparent substrate; and bonding the first transparent substrate
and the second transparent substrate, wherein the lower transparent
electrode includes a conductive composition.
Advantageous Effects
The capacitive touch panel of the invention uses a relatively
inexpensive conductive material compared to an ITO transparent
electrode and has an electrode pattern with a specific structure,
thereby having high visibility as well as cost competitiveness.
Further, according to the manufacturing method of the invention, a
capacitive touch panel having a transparent electrode with high
impact resistance and low total resistance can be manufactured.
DESCRIPTION OF DRAWINGS
FIG. 1 is a cross-sectional view of a capacitive touch panel
according to one embodiment of the present invention.
FIGS. 2 (a) and (b) show patterns of upper transparent electrodes
120 according to one embodiment of the present invention.
FIGS. 3 (a) and (b) show patterns of lower transparent electrodes
140 according to one embodiment of the present invention.
FIGS. 4 (a) and (b) show an overlapping shape of the upper
transparent electrode 120 and the lower transparent electrode 140
according to the embodiment of the present invention.
FIG. 5 shows a graph of spectral transmittance depending on
wavelength according to an inventive example and a comparative
example.
BEST MODE
The above and other aspects, features, and advantages of the
present invention will become apparent from the detailed
description of the following embodiments in conjunction with the
accompanying drawings. It should be understood that the present
invention is not limited to the following embodiments and may be
embodied in different ways, and that the embodiments are provided
for complete disclosure and thorough understanding of the present
invention by those skilled in the art. The scope of the present
invention is defined only by the claims. Like components will be
denoted by like reference numerals throughout the
specification.
Hereinafter, a capacitive touch panel according to embodiments of
the invention will be described in more detail with reference to
the accompanying drawings.
FIG. 1 is a cross-sectional view of a capacitive touch panel
according to one embodiment of the present invention.
The capacitive touch panel includes a first transparent substrate
110 having an upper transparent electrode 120 and an upper
metal-interconnect electrode on a lower surface thereof; a
transparent adhesive portion 130; and a second transparent
substrate 150 having a lower transparent electrode 140 and a lower
metal-interconnect electrode on an upper surface thereof. Here, the
lower transparent electrode may include a conductive
composition.
The first or second transparent substrate 110 or 150 includes at
least one of glass, polyethylene terephthalate (PET), polyethylene
naphthalate (PEN), polyimide (PI), and acryl.
The glass is tempered glass which is produced by heating formed
plate glass at a temperature of 500.degree. C. to 600.degree. C.
that is close to a softening point thereof, and quenching the plate
glass using compressed cool air to compress a surface of the glass
and apply tensile strain to the inside thereof. The tempered glass
has high bending strength that is 3 to 5 times the bending strength
of common glass, high impact resistance that is 3 to 8 times the
impact resistance of common glass, and improved heat resistance.
Thus, the tempered glass can contribute to improvement in
durability of a touch panel.
In the case where both first and second transparent substrates 110,
150 are formed of glass, the substrates can resist high temperature
in application of the upper and lower transparent electrodes 120,
140 thereto, whereby low resistance transparent electrodes can be
obtained.
The first or second transparent substrate 110 or 150 may be formed
of polyethylene terephthalate (PET).
A PET film is biaxially oriented and thus has various advantages in
terms of heat resistance and manufacturing cost.
When the PET film is used to form the first or second transparent
substrate 110 or 150, the PET film is prepared at about 100.degree.
C.
Although other materials such as PEN, PI, acryl and the like may be
used to prepare the first or second transparent substrate 110 or
150, it is desirable in terms of operational stability, dimensional
stability, anti-precipitation of impurities, and the like that both
the first and second transparent substrates 110, 150 be formed of
glass.
The upper transparent electrode 120 may include indium tin oxide
(ITO) or a conductive polymer. The transparent electrode refers to
a thin film electrode, the first and second transparent substrates
110, 150 of which are transparent and have conductivity. That is,
the transparent electrode is a transparent conductive film that may
include ITO or alternatives such as a conductive polymer or
conductive particles. Examples of the conductive polymer may
include polyacetylene, polypyrrole, polyaniline, and
polythiophene.
In the present invention, the low transparent electrode 140 may
include a conductive composition. In this invention, the conductive
composition may include carbon nanotubes (CNTs) or graphene. Such
substances are advantageous due to relative inexpensiveness and
high conductivity as compared with ITO.
The transparent adhesive portion 130 is disposed between the first
and second transparent substrates 110, 150 to bond the first
substrate 110 to the second transparent substrate 150. Since the
capacitive touch panel 100 employs the transparent adhesive portion
130, an air interlayer is not created in the capacitive touch panel
100 as in a resistance film-type touch panel, and the capacitive
touch panel 100 has significantly reduced interface reflectance and
does not suffer glare or non-uniformity due to interference. The
transparent adhesive portion 130 may be formed of an optically
clear adhesive (OCA). When an OCA having a high dielectric constant
is used, a voltage difference between two electrodes increases,
thereby providing a strong electric field.
Referring to FIGS. 2 (a) and (b), the upper transparent electrode
120 includes rhombic patterns 121a, 121b, and upper connectors
122a, 122b disposed between the rhombic patterns to connect the
rhombic patterns. The lower transparent electrode 140 includes
polygonal patterns 141a, 141b, and lower connectors 142a, 142b
disposed between the polygonal patterns to connect the polygonal
patterns.
The upper transparent electrode 120 is formed in the rhombic
patterns 121a, 121b, which are connected to each other by the lower
connectors 142a, 142b disposed therebetween. In addition, referring
to FIGS. 3 (a) and (b), the lower transparent electrode 140 is
formed in polygonal patterns 141a, 141b, which are connected to
each other by the lower connectors 142a, 142b disposed
therebetween.
The upper connectors 122a, 122b connect the rhombic patterns
arranged at constant intervals by connecting, for example, vertices
of rhombic shapes to each other. The lower connectors 142a, 142b
are common surfaces between adjoining polygonal patterns which are
continuously arranged.
The upper transparent electrode 120 is formed by arranging a
plurality of rhombic patterns 121a, 121b, each of which is
elongated in a longitudinal direction, at regular intervals in the
longitudinal direction. Namely, the upper transparent electrode 120
is formed by the rhombic patterns 121a, 121b, which are arranged
parallel to each other in the longitudinal direction on a frontal
area of the first transparent substrate 110, and are electrically
connected to each other by the upper connectors 122a, 122b in the
longitudinal direction.
The formation of the rhombic patterns 121a, 121b on the upper
transparent electrode 120 may increase density of an electric field
emitted from the lower transparent electrode 140.
The lower transparent electrode 140 is formed by continuously
arranging a plurality of plurality of polygonal patterns 141a,
141b, each of which is elongated in a transverse direction. Namely,
the lower transparent electrode 140 is perpendicular to the upper
transparent electrode 120 on an area of the backside of the second
transparent substrate 150, and is formed by the polygonal patterns
141a, 141b, which are provided parallel to each other in the
transverse direction and electrically connected to each other by
the lower connectors 142a, 142b in the transverse direction.
The lower transparent electrode 140 may have various polygonal
shapes, such as a triangular shape, rectangular shape, pentagonal
shape, hexagonal shape, octagonal shape, and other angled shapes
according to design conditions. A diagonal length of the rhombic
pattern, which is provided to the upper metal-interconnect
electrode of the upper transparent electrode 120, can vary
according to the polygonal pattern provided to the lower
metal-interconnect electrode of the lower transparent electrode
120.
In the capacitive touch panel of the invention, the upper
transparent electrode 120 may have a smaller area than the lower
transparent electrode 140. The lower transparent electrode 140
coated with a conductive material is disadvantageous in terms of
thickness adjustment, as compared with the upper transparent
electrode 120 formed of ITO, and there is a difference in
visibility between a surface processed during formation of the
lower transparent electrode 140 and an unprocessed surface. Thus,
it is desirable that the processed area be as small as
possible.
FIG. 4 shows an overlapping shape of the upper transparent
electrode 120 and the lower transparent electrode 140 according to
the embodiment of the invention. In the present invention, the
rhombic patterns 121a, 121b of the upper transparent electrode 140
and the polygonal patterns 141a, 141b of the lower transparent
electrode 140 may not overlap each other. However, it is desirable
that in such an arrangement, the upper connectors 122a, 122b and
the lower connectors 142a, 142b overlap each other such that the
upper transparent electrode and the lower transparent electrode are
electrically connected to each other. When a crossed area between
the upper transparent electrode 120 and the lower transparent
electrode 140 is small, a moire phenomenon that can occur due to
simple repetition of continuous identical patterns can be
restricted and total resistance can be reduced.
Further, with the electrode patterns as shown in FIG. 4, the lower
transparent electrode composed of a conductive composition may also
have improved visibility and the electrode patterns may properly
cope with touch action at multiple points.
In accordance with another aspect of the present invention, a
method of manufacturing a capacitive touch panel includes: forming
an upper transparent electrode 120 and an upper metal-interconnect
electrode on a lower surface of a first transparent substrate 110;
forming a lower transparent electrode 140 and a lower
metal-interconnect electrode on an upper surface of a second
transparent substrate 150; and bonding the first transparent
substrate to the second transparent substrate, wherein the lower
transparent electrode includes a conductive composition.
To provide a transparent electrode structure of a touchscreen
according to the invention, the upper transparent electrode 120 and
the lower transparent electrode 140 are formed on the lower and
upper surfaces of the first and second transparent electrodes 110,
150, respectively, by any one of methods including CVD or PECVD,
spraying coating, air-jet coating, gravure offset coating, rotary
screen coating, and silkscreen coating, which can be properly
selected according to the kind of material forming the transparent
electrode.
When the upper transparent electrode 120 is formed of an ITO film,
plasma discharge sputtering is generally used. In sputtering, high
voltage is applied to a film-forming material, that is, a target,
in a vacuum created using a vacuum device. Then, an ionized inert
gas is formed to collide with a surface of the target, followed by
depositing a material, which is removed from the target, onto a
substrate, thereby forming a film on the substrate. Sputtering
shows excellent performance in terms of widthwise uniformity and
stability in long-term processing (in a flowing direction), and
thus is suitable for long-term and stable manufacture of wide
films.
When the lower transparent electrode 140 is formed of a CNT film or
a conductive polymer, the lower transparent electrode 140, which is
pre-patterned by air jet printing, spray printing, rotary screen
printing, silkscreen printing, or the like, may be placed on the
second transparent substrate. Then, the lower transparent electrode
having a polygonal pattern may be formed by laser etching. As
described above, the lower transparent electrode has as small an
etching area as possible.
After the transparent electrodes are formed and patterned on the
first and second transparent substrates 110, 150,
metal-interconnect electrodes are formed on the first and second
transparent substrates 110, 150 over a region excluding a display
screen region to minimize resistance of the electrodes. If the
metal-interconnect electrode has a wide wiring area as a signal
line, an effective area of a display to be used together with a
capacitive touch panel can be small. Thus, advantageously, the wire
lines have as small a line width as possible.
The upper and lower metal electrodes may be formed by typical
roll-to-toll printing or inkjet printing, air jet printing, spray
printing, offset printing, gravure offset printing, reverse offset
printing, rotary screen printing, and the like. Each of the upper
and lower metal-interconnect electrodes may have a thickness of 100
.mu.m or less. The upper and lower metal-interconnect electrodes
may be formed by coating or depositing at least one of elemental
materials including Cu, Ni, Al, Cr, Mo, Ag and Au.
Roll printing is a method in which a roller rotates along a
substrate such that a material adhered to the surface of the roller
is transferred to the substrate. Use of such a roll printing method
enables elimination of a complex process such as photolithography
and can minimize the line width of the metal-interconnect
electrode.
In a printing technique such as inkjet printing, air jet printing
and spray printing, a conductive ink is sprayed by a nozzle to form
a metal interconnect. The printing technique may more precisely
form an interconnect electrode in a simple, inexpensive process and
with minimal consumption of materials. Thus, it is possible to
minimize the line width in formation of the metal-interconnect
electrode.
The first and second transparent substrates may be bonded together
by any method publicly known to those skilled in the art.
The present invention is not limited to the embodiment shown in the
accompanying drawings, and should be defined only by the
accompanying claims and equivalents thereof. It will be understood
by those skilled in the art that various modifications, changes,
alterations and equivalent embodiments can be made without
departing from the scope of the present invention.
EXAMPLE
A first transparent substrate, which includes an upper transparent
electrode with upper rhombic patterns 121a and an upper
metal-interconnect electrode formed by silkscreen printing, and a
second transparent substrate, which includes a lower transparent
electrode with lower polygonal patterns 141a and a lower
metal-interconnect electrode formed by silkscreen printing, were
prepared. Then, with the upper transparent electrode and the lower
transparent electrode bonded to each other via an OCA (acryl type),
a capacitive touch panel was prepared using a vacuum laminator
(Model No. LM S 110.times.150, NPC).
Comparative Example
A capacitive touch panel was manufactured in the same manner as in
the example except that a lower transparent electrode had rhombic
patterns 121a.
Experimental Example
Evaluation of Visibility of Capacitive Touch Panels
Each of capacitive touch panels prepared in the example and the
comparative example was cut to specimens having a size of
10.times.10 (width.times.height), which in turn were evaluated as
to transmittance of sunlight at an overlapping area and a
non-overlapping area between the upper and lower transparent
electrodes using a UV-VIS spectral transmittance tester (Shimadzu
Co., Ltd.).
Here, visibility was evaluated as follows. In measurement of the
transmittance of sunlight at the overlapping area and the
non-overlapping area between the upper and lower transparent
electrodes, a difference of less than 0.5% was evaluated to be high
visibility, and a difference of 0.5% or more was evaluated to be
low visibility.
Further, resistance linearity (uniformity) was measured for the
example and the comparative example using a resistance tester
(available from VITRON Co., Ltd.). Specifically, capacitive touch
panels of the example and comparative example were manufactured in
a longitudinal direction and a difference (.DELTA.E) in voltage
variation depending on distance was obtained when a DC voltage of 5
V was applied across both ends of the modules.
Here, an electric field was created towards the lower transparent
electrode due to impact (touch) of the upper transparent electrode.
It was evaluated such that the transparent electrode pattern had
good performance when it could easily perceive impact strength.
That is, a perception rate for an impact position was evaluated to
be good, when a voltage change with respect to a distance from the
impact position is small and linearity by voltage increases.
TABLE-US-00001 TABLE 1 .DELTA.E 10 mm 20 mm 30 mm 40 mm 50 mm
Average Ex. 1.0 1.3 1.2 1.0 1.3 1.16 Com. Ex. 1.1 1.5 1.1 1.5 1.1
1.26
Referring to Table 1, in the example, when measuring spectral
transmittance at a wavelength of 550 nm, a difference in
transmittance of sunlight at the overlapping area and the
non-overlapping area between the upper and lower transparent
electrodes was less than 0.5%. On the contrary, in the comparative
example, the transmittance was reduced at the overlapping area
between the upper and lower transparent electrodes. Specifically, a
difference in transmittance at the overlapping area and the
non-overlapping area between the upper and lower transparent
electrodes at a wavelength of 550 nm was 3%.
As a result, it could be seen that the example, in which the upper
transparent has a smaller area than the lower transparent
electrode, and the rhombic patterns of the upper transparent
electrode and the polygonal patterns of the lower transparent
electrode did not overlap each other, had higher visibility than
the comparative example in which the upper and lower transparent
electrodes have the same patterns.
Further, as a result of checking a final average value of
differences in a voltage change according to distance with
reference to Table 1, the example had a smaller difference in
voltage change according to distance than the comparative example.
Thus, it could be seen that the example had a good perception rate
at an impact position and provided excellent precision for
perceived position.
Therefore, it could be seen that the patterns of the example, in
which the upper transparent electrode had a smaller area than the
lower transparent electrode, had better performance than the
comparative example, in which the upper transparent electrode had
the same area as the lower transparent electrode.
* * * * *